The past decade has seen an increase in the prevalence of the misuse of prescription stimulant medication (e.g., Ritalin, Adderall), particularly among college students. Research has established several risk factors that may contribute to nonmedical use, though the mechanisms by which these characteristics contribute to misuse are poorly understood. Expectancy effects contribute to the initiation and maintenance of drug use, and are thus important to assess. Research has not yet examined expectancy effects for prescription stimulants. Additionally, no prevention or intervention strategies exist to treat this population. Direct attempts to change expectancies for alcohol use have resulted in decreased drinking behavior, and it is possible that a similar expectancy challenge could be applied to prescription stimulant misuse. The proposed study will address these gaps in the literature by exploring the role of expectancy effects, risk factors, and an expectancy challenge on initiation of prescription stimulant misuse in college students. The specific aims are to: (1) examine the effect of prescription stimulant expectancies on subjective ratings and cognitive performance, (2) explore the contribution of individual risk factors and expectancy effects to prescription stimulant misuse, and (3) to consider the influence of an expectancy challenge on initiation of prescription stimulant misuse. Participants will include 100 northeastern college students between the ages of 18 and 25 who report no history of prescription stimulant use. Data will be collected through self-report questionnaires and participants will undergo a series of cognitive tests. Data will be analyzed using repeated measures MANOVA and logistic regression techniques. Prescription stimulant misuse has significantly increased among college students and is a significant public health concern. Abuse of the medication may not only be detrimental to the user's health and well-being, but those individuals who truly need the medication may suffer, given that many students report obtaining medication from their peers holding a prescription. The information derived from this study will be useful in better understanding prescription stimulant misuse and in developing prevention and intervention strategies that are appropriate for treating this population.